Method and apparatus for straightening plates



Aug. 6, 1929. F. UNGERER METHOD'AND APPARATUS FOR STRAIGHTENING PLATES Filed June' 13, 1928 2 Sheets-Sheet 1929- Q F. UNGEiQER 1,723,098

METHOD AND APPARATUS FOR STRAIGHTENING PLATES Filed June 15, 1928 I 2 Sheets-Sheet 2 Patented Aug. 6, 1929.

' UNITED STATES 1,723,098 PATENT "OFFICE.

FRITZ UNGEIB'ER, OF IPFOBZHEIM, GERMANY.

METHOD AND APPARATUS FOR STRAIGHTENING PLATES.

Application tiled Juiie 13, 1928, Serial No. 285,072, and in Germany May 31, 1927.

machine, the plate being then exposed to considerable tensile forces which strain up to the strain limit of the material the cross-section of some of the plate-sections to be I stretched.

By this method perfect straightening results are seldom obtained, specially with thinner and harder plates. i

It has been found that a very good straightening takes place, when the sheet-metal plate stretched under static pull, i. ,e. statically strained, is submitted to an additional strain of a dynamic kind, for example by means of pulling forces.

The new method can be carried out, for example, so that the plate submitted to pull in the stretching machine is shaken from one clamping point or from both clamping points in the plane of the plate transversely to the stretching direction, the distance betweenv the clamping jaws remaining constant, said jaws carrying out only a vibrating movement in, the plane of the plate the one with regard to the other. The sudden pulls on the plate produced by these shaking movements exert probably a kind of contacting efi'ect,,i. e'. give to the molecules, which up to then were still at rest notwithstanding the strong pull, the impetus to flow into the position, of equal strain.

The shaking movement, which for many kinds of sheet metal need be only very slight, can be produced in various manners. In order not to make the construction of the stretching device very complicated, preferably only one of the two clamping jaws is arranged so that it pan move in transverse direction, this clamplng jaw being connected to a suitable shaking device. Both clamping jaws might howeverfcarry out oppositely directed shaking movements;

To explain the method a'stret'ching device having a shaking arrangement :at one end is illustrated, by way of example, in the accompanying drawing, in which:

Fig. 1 is a front-elevation.

Fig. 2 a top-plan-vie'w.

Fig. 3 a side-elevation and Fig. 4 a section onhne M of Fig. 1a

Fig. 5 shows the eccentric driving mechanism for the clamping element.

'6 is a cross section on line 66 of Fig. 7 shows the clamping jaw in side elevation and Fig. 8 is a part jaw.

The apparatus consists essentially of two main elements, the stretching device -of known type and the shaking mechanism.

end view of the clamping Both devices are arranged in the machine-- frame m which forms a slide a, for the clamping jaws b and 0. The clamping jaw b is at the same time the pulling jaw, and it is therefore connected by pull-rods d with a yokee onto which acts the p'ston g, arranged in the pressure-cylinder The clamping jaw 0 forms at the same time an adjustablejaw and a shaking-jaw. It can be adjusted by means of screw-spindles h and adjusting nuts i to the length of the sheet-metal-plate Z to be straightened.- Its shaking movement takes-place so that it is'moved t0 and fro, together with the screw-spindles h and the yoke is against which the adjusting nutsri press, in the direction of the double arrowline A (FigmQ) i. e. perpendicularly to the strai htening or stretching pull. Wlth this object in view" the yoke k is mounted with regard to the machine-frame a on rollers m engaging with cavities n of the machine-frame so that said yoke can be shifted on the machine-frame a transversely to the stretching direction. The clamping jaw c is driven s well as the yoke k bythe shaking mechanis which consists essentially of two links '0 and p, mounted on the axle-journals o' and p (Fig. 1) and to which, by two eccentrics and 0, an oscillating movementis commun cated.

- A bolt u is mounted in a bore of the yoke k and bridges the recess of the yoke 70 in which 'the rocking lever o engages from below. A

bolt 0 is fixed to the shaking j aw c and bridges the recess of the shaking aw a in which the I ment of these latter which are rigidly connected withthe yoke k and the shaking j aw a is in a straight line .The blocks 8 and t have a bore through which the bolts u and 'v pass freely Further the blocks a and t projefi p are essential in order to convert the oscillating movement of these latter into a reciproeating movement of the yoke Z: and of the shaking jaws c. The oscillating movement of the rocking levels 0 and p is transmitted by the blocks 8, t respectively and by the bolts u, '0 respectively onto the yoke k and through the same onto the shaking jaws 0. The eccentrics q and?" are driven by a common shaft w,

journalled in the machine-frame a.

The eccentric 1" is secured against rotation on the shaft 'w but is shiftable in longitudinal direction so that it can follow the adjusting movement of the shaking jaw 0 when it is brought into the proper distance from the clamping jaw 12 according to thel'ength of the sheet metal plate Z.

The construction of the mechanisms which produce the shaking movement is as follows a The clamping jaw c is first shaken in the direction A (Fi 2), however the jaw 0 is connected with screw-spindles h for the purpose of adjustment at the correct distance, these screw-spindles h as also the yoke 70 and the adjusting nuts i must follow the shaking movement in the direction A. The screwspindles It therefore do not pass through ti ht fitting holes in the machine frame a, but

through holes which are large enough not to hinder in any way the mutual shaking movement of the clamping jaw c of the screwspindles h, of the yoke la and of the nuts 71 (Fig. 2). For shaking this whole system of machine parts the shaking drive is only. ef-

fected at two points of this system, namely,

firstly, on the yoke 7: which never changes its dlstance from the clamping aw b, and on the clamping jaw a the distance'of which fromv the clamping jaw I) must be changed by turning' the nuts 2' according to the length of the sheet metal-plate Z. Seeing that the clamping jaw I) does never change its relativeposition it isnot necessary that the eccen ric (1, which effects the shaking drive of th yoke 70, be slidable on the driving shaft w but it is keyed thereto in known manner. On the other hand however the eccentric 1 which eifects the shak- -i'ng drive of the clamping jaw b must be slidable on the shaft w if the clamping jaw 0 is turning the nuts adjusted in relation to the clampingj aw b by The connection of the eccentric 1' with the shaft w must be such that it follows the rotating movement of the shaft 41) and yet is longitudinally slidable on this shaft w.

togetherwith the supporting bearings w yet is compelled to follow the rotarymovements of said shaft w. The carriage a: formed by the supporting bearings a" consists of two flanged parts connected together at suitable points e. g. by means of screw-bolts w and nuts :0 and held at a distance apart by distance sleeves In order that the element of the shaking device coordinated to the shaking jaw 0 can follow the adjusting movements of the shaking jaw c, produced by the adj usting nuts 2', the link 7) is mounted in a. carriage 00, shiftably, suspended in guides a of the machine-frame a and forming at -the same time a supporting bracket :22 for that portion of the driving shaft w which actually carries the eccentric 1'.

The straightening is carried out in the following manner:

The distance between the clamping aws and c is adjusted according to the length of the sheet metal-plate Z, whereupon this plate is clamped in the mouths of the jaws b and 0 with the aid 1 of commonly used clamping means. The clamping jaw-0 is for example composed of a lower part 0' and an upper part 0 Alocking member comprising a cylindrical rear part c and a serrated front portion 0 eccentric to the axis of the cylindrical rear portion 0 is oscillatably mounted in a recess 0 in the upper part c of the jaw 0, so that if the jaw c is moved in the direction of the arrow B (Fig. 7) the serrated portion 0 will approach the serrated surface 0" of the lower part 0'. A handle c is keyed to the reduced end 0 of the rear portion 0 and serves to open or close the jaw formed between the pressing surfaces 0 and 0 according to the direction of turning. Theunore the sheet metal-plate Z is subjected to pull, the tighter will the eccentric pressure surface 0 press against the end of the sheet metal-plate, thus ensuring a secure holding of the plate. Needless to say other suitable means of clamping the plate may be used. Hydraulicpressure is then applied on-the piston g and increased, in observing a pressure-gauge, until the tensilestress required for straightening the plate has been attained. At this moment the shaft 'w is connected to a source of power, which communicates a rapid rotating movement to said shaft, this rotating movement being transmitted by the rapidly oscillating shaking jaw a as shaking movement onto the plate Z. This shaking brings the molecules of the material of the sheet metal plate which are still in the static state to flow into the position of equal straining and compensates consequently the tensions completely, so that the plate removed from the apparatus is straightened so as to extend in a single plane.

I claim 1. A method for straightening plates consisting in submitting the sheet metal plate to a static straightening pull, i. e., making it statically strained, and then subjecting the.

' plate to an additional strain While so statical- -ly strained by shaking the plate to produce pulls acting in the plane of the plate.

2. A method as specified in claim 1, in which the pulls exerted on-the plates are produced by shaking the same from one clamping point.

3. A method asspecified in claim 1, in which the pulls exerted on the plates are produced by shaking the same from one clamping point in the. plane of the plate and transversely to the stretching direction.

4. A machine for carrying out the, method described, comprising amachine frame, a

stationary clamping jaw on said frame, an

adjustable clamping jaw on the frame, an adjusting mechanism for said adjustable clamping-jaw consisting of'screw-spindl'es' and adjusting nuts associated therewith, a

yoke on said machine-frame adapted to be adjusted transversely to the direction of movecentric for communicating to said link a reciprocating oscillating movement. Ii'i testimony whereof I afiix my signature.

FRITZ UNGERER. 

